This invention relates in general to a capacitor's container and in particular to a new and useful process for hermetically sealing an electrical component container with a lid and to a capacitor winding sealed container construction.
A similar can-shaped housing for an electrical component, especially for capacitors, with an outward-protruding rim, that is sealed hermetically with a lid and a gasket between the lid and the housing rim, is known from German Patent No. 879 733. For the closure, the metal lid must be pressed against the housing, so that a suitable sealing pressure is exerted on the gasket, whereby a part of the lid that overlaps the housing rim is formed into a bead behind the rim. Such a closure is unsuitable for the efficient manufacturing of electrical components. It is even less suitable when the cross section of the can-shaped housing has an oval-cylindrical shape. Furthermore, if the lid is made of plastic, a beading is possible only by a hot pressing process (German Patent Application P No. 35 16 658.4).
The brochure of Branson Schallkraft GmbH, D-6056 Heusenstamm, "Economical Bonding of Plastics", discloses how to bond thermoplastic materials; bonding can be done by ultrasonics in particular.
Despite the multiple applications of plastic welding, it has not been used heretofore to seal the housing of electrical components with a lid, specifically for capacitors impregnated with fluid insulating oil. On the one hand, the can-shaped housing is made of metal for definite reasons, so that a hermetic weld is out of the question for that reason; on the other hand, it has been suspected that the materials may have negative electrical effects on the insulating oil that occur because of an increase in tan .delta. from extractable substances during the bonding, and that various impregnating fluids in the housing, such as isopropylbiphenyl, for instance, will interfere with the bonding procedure or prevent a hermetic seal.